Scaling and root planing for the removal of calculus and contaminated root cementum are essential procedures in the treatment of periodontal diseases. For this purpose, dental curets are used for orthogonal cutting of the root surfaces, a method that removes thin chips of contaminated cementum.
This root planing procedure dulls the cutting edge of the curets which, for proper cutting action, have to be sharpened at frequent intervals. Up to now such sharpening action has been done as a free-hand procedure, with or without guide plates, resulting in edges of inferior sharpness and incorrect edge angles with serious aberrations from the ideal shape of the cutting blade. Although machines have been proposed to help in the process of sharpening curets, until now, no machine could accurately and efficiently produce a sharp cutting edge on any of a series of curets with different rake angles. See, for example, U.S. Pat. Nos. 1,350,951; 2,114,757; 2,578,309; 4,535,570; and 2,380,988.
A variety of dental curets of different shapes are available on the market, but there is no one single set of curets that in a systematic and logical way guides the operator in the selection of instruments needed for optimal efficiency in the different areas of the oral cavity. See, for example, U.S. Pat. Nos. 1,605,320; 1,495,115; 1,138,355; and 2,366,671.
Most curettes on the market are double-ended, i.e., comprise a longitudinal handle with a cutting blade at the distal end of a shank, which is secured to each end of the handle. The handles usually are made out of metal tubing, the surface of which is processed to give different patterns of groves and ridges to increase the friction when holding the curettes during the scaling and root planing procedures.